The present invention relates to an electronic appliance, and more particularly to an electronic appliance using printed wiring boards.
Recently, as the electronic appliances are diversified and the dining industry is growing, there is a mounting demand for reliability of electronic appliances used in the professional kitchens, restaurants and others, and insect countermeasures are required in the electronic appliances.
In the electronic appliances used in household kitchen, unpleasant and harmful insects such as cockroaches may cause troubles on electronic appliances. Moreover, electronic appliances used continuously by feeding a feeble current are increasing in number, and the electronic appliances are installed in the living room or other living environments. In winter, in particular, electronic appliances may be a comfortable habitat for insects preferring the warmer place.
However, little has been considered about measures against insects invading into electronic appliances. Troubles of electronic appliances due to dead bodies or wastes of insects were hardly made public. Accordingly, insect countermeasures were not generally applied within the electronic appliances. Only the shape of the housing of electronic appliances was slightly modified for this purpose.
As measures for repelling insects, structural designs have been hitherto considered, such as enclosure of electronic appliances, and placing of shielding plates to prevent invasion of insects onto the printed wiring board after mounting of parts. As the electronic appliances are becoming more and more smaller, such measures are difficult. In particular, many electronic appliances have restrictions such as necessity of cooling of electronic circuits and structure of appliance, and it is difficult to design electronic appliances having no opening, hole or gap, and it is impossible to constitute electronic appliances completely shutting off the cooling parts and opening parts.
Insects, once invading into the electronic appliance, can hardly get out. In particular, baby cockroaches get into the electronic appliances from tiny gaps, and grow up in the electronic appliances. In this way, cockroaches proliferate in the electronic appliances. When these insects or dead bodies contact with live parts or high voltage parts of the electronic appliance, it may lead to malfunction, heat generation, or other troubles.
Conventional measures for repelling insects include, among others, a method of applying an insect repellent paint on the housing, a method of adhering a repellent tape to cover the gap, bottom hole or opening of electronic appliance, a method of using a packing member or sealing member adsorbing a repellent on the housing. Such measures, however, require a larger size for the electronic appliance, being contrary to the recent need for smaller size and lighter weight. Yet, if insects invade into the electronic appliances, insects build up nest, and nesting cannot be prevented by such measures.
It was also attempted to mold the printed wiring board containing electronic components with an insect repellent paint after forming an electronic circuit by mounting electronic components on the printed wiring board. Such conventional measures are accompanied by lowering of insulation reliability of printed wiring board due to molding of insect repellent, deterioration of durability, drop of cooling performance of heat generating parts such as electrolytic capacitors and power transistors, dissipation of repellent chemical due to heat generation of printed wiring board, lowering of insect repellent effect due to evaporation of repellent chemical, increase in the number of processes after mounting, and difficult of inspection of electronic circuit. Ultimately such measures were not widely employed.
An electronic appliance of the invention comprises (a) a housing, and (b) a printed wiring board having an electronic material containing a repellent, and an electronic circuit having electronic components mounted on the printed wiring board. The electronic circuit is placed in the housing.
Preferably, the electronic material is at least one selected from the group consisting of paste, solder resist, parts layout, insulating resin, prepreg, and resin film.
Preferably, the electronic components have heat generating parts.
Preferably, the housing has at least one of an opening and a penetration hole for placing components.
In this constitution, without lowering the quality characteristic of the printed wiring board, the printed wiring board itself is effective to prevent nesting by insects. It is also possible to reduce in size and weight, and an electronic appliance having excellent repellent effects is obtained. In and after mounting process, electronic components are free from adverse effects, and an electronic appliance having an excellent repellent effect is obtained. The cooling performance is not impaired, and an electronic appliance having an excellent repellent effect is obtained.
That is, even after mounting electronic components on the printed wiring board, the reliability of the electronic components and electronic circuit is not lowered, and nesting suppressing effects of insects in the electronic appliance are maintained, and the rate of troubles due to insects is lowered, and the electronic appliance capable of enhancing the cleanliness around the appliance is obtained.